SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c05cb2ba19869db25e3d99f18708befee59594d667c51db2b5481573bc16868f' 
  AND token = '6FS9dtPxtq/YqFdxFyuXv/eAyGJsPGen1ryzCrQaIX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}